Method of making insulator pins



Dec. 13, 1927. 1,652,835

C. L. PEIRCE, JR

METHOD OF MAKING INSULATOR PINS Filed May 31, 1922 Patented n... 13,1927.

UNITED STATES PATENT OFFICE.

METHOD MAKING INSULATOB PUB.

' Application filed Kay-81,

This invention relates to insulator supports and more particularly to insulator support pins for use with the ordinary internally threaded insulators used for supporting electric transmission lines.

There is a growing demand for insulator pins of the above type equipped with lead threads and so far as I know, prior to the invention of this application, the onlyv method of applying lead threads to insulator pins has been to cast the threaded lead portion onto the pin. This is a relatively slow process and is expensive.

Many attempts have been made to provide satisfactory means for securing insulators to supports and in endeavoring to accomplish this, supports have been provided with yielding threads. Such threads are not, however, thoroughly satisfactory and an object of this invention is to provide attaching means for insulators which is better adapted for the purpose than other .such means now in use and known to me.

A further and more specific object is to more economically and effectively produce an attaching means for insulators which is softer than the support and the insulator supported thereby.

A still further object is to produce a new and improved method of forming and rigidly securing an insulator attaching member to an insulator support in which a material softer than the support and softer than the insulator is forced or pressed into gripping engagement with the su port and is formed into an'attaching me'm er by compression after being located on the support.

In the drawings accompanying and forming a part of this application, Figure 1 is a side view of a typical unthreaded cross arm pin. Figs. 2, 3, 4, 5 and 6 illustrate difierent steps in the method of providing such a pin with lead threads in accordance with this invention. Fig. 7 illustrates one 4 step in the method of providing lead threads on a pressed metal insulator support arm and Fig. 8 illustrates one step in a modified method falling within this invention.

In practicing my method the support end 9 of any suitable cross arm pin is-notched or roughened as shown at 10. Figs. 2, 4 and 8. A lead sleeve 11 of suitable length, and suitable thickness to provide the necessary 1822. Serial No. 584,888.

threads is cut from a piece of lead pipe or formed m an automatic machine. The internal diameter of the sleeve is such that the sleeve may be readily slipped over the end of the cross arm pm. The pin with the encircling sleeve is then inserted within dies 12 and 13 included in a suitable power press and by means of the dies, which are provided with suitable internal threads 14, the sleeve 11 is compressed so as to intimately contact with the roughened or notched portion of the pin and the threads 15 are formed in the sleeve.

The metal of the sleeve is caused to flow longitudinally of the pin and into the depresslons or notches formed in the pin, and to flow into the internal threads of the die members.

The end of a pin with the completed lead threads thereon is illustrated in Fig. 6.

In Fig. 7, a lead sleeve 11 is shown enelrcling the outer end ofa pressed steel msulatorsupport arm 16.

Instead of utilizing a sleeve such as sleeve 11, a lead thimble 17 having an end 18 may be utilized. Such thimbles can be readily cast in an automatic machine and used in place of the sleeve. The operation in the die will be the same as when the sleeve is used and the resulting product will, to all intents and purposes, be the same.

This method, it will be seen, readily adapts itself to supports or cross arm pins of any cross section, whether round, square or irregular as the lead under die pressure will flow and fill the space between the support and the dies.

Having thus described my invention, what I claim is 1. The method of forming a screw threaded end on an insulator support which .con-

sists in notching the surface of a support adjacent one end thereof so as to provide a gripping surface thereon, loosely encircling said roughened end with a sleeve of relatively soft metal, compressing said sleeve so as to cause the inner surface thereof to flow into said notches and grip the roughened end of said support and compressing the exterior surface of said sleeve so as to form screw threads thereon.

2. The method of forming an insulator support which consists in providing a plurality of staggered notches adjacent one end soft metal and forging said sleeve so as to cause the metal thereof to flow into said staggered notches and grip the roughened end of said pin and simultaneously shaping the outer surface of said sleeve so as to form insulator receiving screw threads. 10

In' testimony whereof, I have hereunto subscribed my name this 25th day of May,

CHARLES L. PEIRCE, JR. 

